138 MISSOURI BOTANICAL GARDEN 



Series No. 2. Copper nitrate. Where the copper nitrate struck the 

 leaves the tissue underneath was killed entirely (plate 28, fig. 1). Where 



inflnitesimally small drops struck the surface of the leaf, eruptions the 

 size of a pin began to form. 



Series No. 3. Copper acetate. The copper acetate solution practi- 

 cally killed the leaf surface wherever it struck in any quantity. Where 



very small drops struck the surface, exceedingly minute eruptions began 

 to form. 



Series No. 4. The copper chloride solution killed the leaf surface 

 wherever the solution struck the leaf (plate 30, flg. 2). Where the 

 spray stuck to the leaves in small drops eruptions started. This was 

 particularly true of the very young leaves. 



Series No. 5. Copper sulphate. Plants sprayed with copper sul- 

 phate had practically the same appearance as those sprayed with copper 

 chloride and copper nitrate. The sprayed areas were practically killed 

 where the spraying solution had adhered, except where very small 

 quantities of spray stuck to the leaf. It was very striking that not only 

 were the areas immediately touched by the spray killed, but all adjacent 

 areas, as if there had been a decided diffusion of the salt through the 

 leaves (plate 30, fig 1). 



Series No. 6. 10% ammonia. Leaves sprayed with 107* ammonia were 

 killed outright in the region touched by the spray (plate 29, fig. 2). 

 Very definite circumscribed spots as shown in the figure were formed. 

 Absolutely no sign of any eruptions. 



Series No. 7. 2% ammonia. After four days there was practically 

 no sign of any change in the leaves sprayed with 2% ammonia. Several 

 days later, however, most decided eruptions formed on these leaves 

 and developed in the characteristic manner. 



Series No. 8. Ammonium carbonate. The younger leaves showed 

 decided eruptions in blotches wherever the spray struck the leaf. 

 These were beginning to stretch through the epidermis much as the 

 small warts did with the ammonium copper carbonate. 



The sprayed plants were examined daily for a period of 

 two weeks and the general conclusions drawn 

 follows : 



Plants sprayed with the copper salts without the addi- 

 tion of ammonia were generally killed where the spray 

 struck the leaf areas in any quantity. Where very minute 

 quantities of the spray touched the leaves, eruptions 

 formed. The plants sprayed with ammonia were killed 

 when the stronger solution was used, but the weak solution 

 produced characteristic eruptions. The ammonium copper 

 carbonate produced decided eruptions wherever used . 



were as 



